Sunflower Star Going for a Walk

One of the sunflower stars living at the invertebrate house at the Smithsonian National Zoo.

(from Wiki:)

Sea stars move using a water vascular system. Water comes into the system via the madreporite. It is then circulated from the stone canal to the ring canal and into the radial canals. The radial canals carry water to the ampulla portion of tube feet.

Tube feet consist of internal ampulla and external podium, or "foot". The ampulla squeezes forcing water into podium, which expands to contact substrate. Although the podium resembles a suction cup, gripping action is a function of adhesive chemicals rather than suction. De-adhesive chemicals and podial contraction allow for the release off of substrate.

The tube feet latch on to surfaces and move in a wave, with one body section attaching to the surfaces as another releases. Most sea stars cannot move quickly. However, some burrowing species from the genera Astropecten and Luidia are capable of rapid, creeping motion: "gliding" across the ocean floor. This motion results from their pointed tubefeet adapted specially for excavating patches of sand.

Category:

Pets & Animals

Tags:

• animals
• starfish
• sunflower star
• ocean
• aquatic life
• zoo
• aquarium
• smithsonian national zoo
• fuu-chan